In recent years, new 3C products integrated with a touch panel are launched constantly to meet market requirements, and manufacturers introduce various types of 3C products integrated with the touch panel are introduced to the market continuously due to the severe market competition. Among these products, a multi-touch sensing system uses a camera to capture a light spot produced by the touch of a user's moving fingers on the touch panel, and execute a corresponding the operation instruction according to the motion trajectory of the light spot. However, the conventional touch systems still have many drawbacks.
R.O.C. Pat. No. M399375 discloses a display touch system that uses a photo sensor and a camera to detect a touch point of a user's finger and calculates a change of displacement and speed of the user's finger. However, if the number of touch points increases, then the number of required photo sensors must also increase to improve the recognition rate, thus increasing the cost and reducing the flexibility of using the system.
R.O.C. Pat. No. M398155 discloses an optical touch system that uses a laser sensing module and one or more sensing units to detect a photo interrupt point on a sensing area to determine the position of a touch point. However, if many fingers are moved in the detecting area at the same time, a detection error of the sensing unit may occur easily due to the masking between fingers.
U.S. Pat. No. 7,598,949 discloses a multi-touch LED display device that uses a plurality of emission type LEDs and sensing type LEDs to create a sensing area to sense coordinates of a finger that touches the sensing area, and requires two or more cameras to capture information of the touch interface. However, when the ambient light of the LED varies, wrong determinations may result, and if the number of touch points increases, the camera may be unable to capture the information or may cause errors due to the masking between the touch points.
Therefore, it is a subject for the present invention to provide a multi-touch sensing system capable of detecting a touch bulb produced by a plurality of fingers moving in a detection area without requiring additional components, while maintaining excellent stability and applicability in different illumination conditions or in a condition of being affected by infrared noises.